Tandem motor

[Mikey182]

Hey, thought I'd ask for some opinions and advice on a motor, ideally rear hub for our tandem.
I recently purchased a yose 250w front hub motor with 36v battery for the wifes bike. I admit I love the kit and all works well. I recently tried it on our tandem on a couple of local rides. About 10-20 miles. It was fine for a flat ish ride of about 20 miles and 1800ft of climbing. We even returned with nearly a full battery. However on a more recent ride of about 12miles but the same elevation. The lack of torque was really noticeable. On the flat we dont need the motor at all. Tandem as I'm sure you are aware are fast rolling. Just on the hills we could use the extra power to help with the weight.

A few points to add.
-i would prefer if possible to stick to 36v to keep the existing battery 36v 12.5ah hl
-could do with at least 500w or just double the torque ( not sure what motor or rpm this is) hence me thinking of a geared hub
-the hose hub comes on a wheel that offers both disk and rim breaking so I was hoping to have similar and attach a rear disk aswell as a stoker brake for the wife to help with long descents.
-is their any difference in the 250w/350w yose wheels?
-Has to be 28"(700c)
-Bike weight is about 22kg
-Riders weight is combined @130kg (sometimes I carry the dog in backpack, she weighs 27.5kg)

Thanks for any help you can give, Mike.

 

[Wicky]

Hey, thought I'd ask for some opinions and advice on a motor, ideally rear hub for our tandem.
I recently purchased a yose 250w front hub motor with 36v battery for the wifes bike. I admit I love the kit and all works well. I recently tried it on our tandem on a couple of local rides. About 10-20 miles. It was fine for a flat ish ride of about 20 miles and 1800ft of climbing. We even returned with nearly a full battery. However on a more recent ride of about 12miles but the same elevation. The lack of torque was really noticeable. On the flat we dont need the motor at all. Tandem as I'm sure you are aware are fast rolling. Just on the hills we could use the extra power to help with the weight.

A few points to add.
-i would prefer if possible to stick to 36v to keep the existing battery 36v 12.5ah hl
-could do with at least 500w or just double the torque ( not sure what motor or rpm this is) hence me thinking of a geared hub
-the hose hub comes on a wheel that offers both disk and rim breaking so I was hoping to have similar and attach a rear disk aswell as a stoker brake for the wife to help with long descents.
-is their any difference in the 250w/350w yose wheels?
-Has to be 28"(700c)
-Bike weight is about 22kg
-Riders weight is combined @130kg (sometimes I carry the dog in backpack, she weighs 27.5kg)

Thanks for any help you can give, Mike.

simple tandem conversion

We are thinking of converting our fairly basic tandem to electric. We won't be doing huge mileages, fast riding or big hills (Winchester area), but help on the smaller hills will be welcome. Combined rider weight around 155kg (24 1/2 stone). Ideally I want a front wheel conversion, as it is...

www.pedelecs.co.uk

 

[Woosh]

It's very difficult to generate high torque for a tandem with 36V battery.

best kit for tandem:

https://wooshbikes.co.uk/cart/#/product/uid-241-dwg22c-48v12ah/shengyi-dwg22c-48v-250w-rear-hub-kit-with-48v-12ah-battery

battery (48V 12AH) is good for 50 miles from a full charge.

 

[sjpt]

All 250w motors generate much more than that at peak (400w to >700w); and might actually be the same as motors marked 350w.

I think most Yose hub motors are geared; are you sure yours isn't? The gearing and winding details of hub motors makes a big difference to their hill climbing capability for the same power. Gain for hills will lose out for flat speed, but you probably don't care.

A crank drive motor would mean the motor was using the gears, good for hills. But could well be awkward to fit with typical tandem crossover drive.

A BPM front from Woosh might do the job. I think that is now a legal nominal 250w. (I see he has already made another suggestion while I was typing.)

We've got a Mxus XF07 from Woosh on the front of our tandem. It helps a lot, but we still need our bottom gears and lots of effort on steeper hills. We knew when we bought that it was a bit under ideal power, but there wasn't much choice in 700c wheels at the time. Also it was our first electrification so we wanted to keep things simple, and keep costs down as we weren't sure we'd like it (we do!).

I think our tandem is heavier than yours (our basic Viking is probably around 30kg), and we add up to nearer 160kg (and 140 years) between us. But no dog, and we haven't tried taking the cats.

With different weight distribution on the tandem you don't get the disadvantage of slipping on front hub motors; plus you get two wheel drive (motor front, us back) which has often helped us out on slippery grass tracks.

 

[Mikey182]

simple tandem conversion

We are thinking of converting our fairly basic tandem to electric. We won't be doing huge mileages, fast riding or big hills (Winchester area), but help on the smaller hills will be welcome. Combined rider weight around 155kg (24 1/2 stone). Ideally I want a front wheel conversion, as it is...

www.pedelecs.co.uk

Thanks for the link. I had already read this but I didn't really find that it helped me that much to understand. And I was also hoping things might have moved on and new motors etc.

 

[Mikey182]

All 250w motors generate much more than that at peak (400w to >700w); and might actually be the same as motors marked 350w.

I think most Yose hub motors are geared; are you sure yours isn't? The gearing and winding details of hub motors makes a big difference to their hill climbing capability for the same power. Gain for hills will lose out for flat speed, but you probably don't care.

Thanks. Yeah I think it is geared, however just wasn't enough to get us up the hills where we really need it! live in a very hilly area. most hills are probably over 10% and the average for the one we tried was just over 12 but it wasn't enough. Top speed is of no importance to me just having extra torque. im not fussed about going up a hill fast, just to maybe make it at 5mph without blowing out my backside. Thanks for the advice

 

[Mikey182]

It's very difficult to generate high torque for a tandem with 36V battery.

best kit for tandem:

https://wooshbikes.co.uk/cart/#/product/uid-241-dwg22c-48v12ah/shengyi-dwg22c-48v-250w-rear-hub-kit-with-48v-12ah-battery

battery (48V 12AH) is good for 50 miles from a full charge.

Thanks, ill take a look. would this be better than a higher wattage?

 

[Woosh]

don't pay any attention to the wattage, it just marketing like how many Watts you get out of your loudspeakers. The quality of the bass depends a lot more on the quality and quantity of the speakers' magnets.
The kit I sell is 250W.
You need the motor optimised for the job which is the most power and torque at 14mph-15mph.
for that, you need to choose the right motor winding so that Kv * V = 200 RPM. If V is 30% higher, Kv can be 30% smaller, that means 30% more spires = more copper wire = stronger magnetic field = higher torque, especially at low revs.
My DWG22C and my SWX02 have a lot more copper wire than your motor. They are powered with Lishui 48V 17A controller so when you go up a hill, the DWG22C can pack a bigger punch.

 

[Mikey182]

don't pay any attention to the wattage, it just marketing like how many Watts you get out of your loudspeakers. The quality of the bass depends a lot more on the quality and quantity of the speakers' magnets.
The kit I sell is 250W.
You need the motor optimised for the job which is the most power and torque at 14mph-15mph.
for that, you need to choose the right motor winding so that Kv * V = 200 RPM. If V is 30% higher, Kv can be 30% smaller, that means 30% more spires = more copper wire = stronger magnetic field = higher torque, especially at low revs.
My DWG22C and my SWX02 have a lot more copper wire than your motor. They are powered with Lishui 48V 17A controller so when you go up a hill, the DWG22C can pack a bigger punch.

Thanks so much for explaining, and please excuse my ignorance. I'm still learning about all this. What casing is the battery in? The kit I tested as explained above is in the hailong. It only just fits within the frame. This gives us something to save up for! Thanks again for all your help! hopefully be buying off you soon.

 

[Mikey182]

Here is a pic of the three of us for reference. Hope it makes you all smile

 

[Woosh]

What casing is the battery in?

same Hailong (HL) casing. The cells are arranged differently.

Woosh hub kits | Electric Bike Conversion Kits from Woosh

Woosh range of hub kits with choice of front or rear hub motors. Convert your bike into an electric bike.

wooshbikes.co.uk

 

[Nealh]

The Yose hubs are quite highly wound for geared hubs and are approx. 280 -300rpm so not enough torque for inclines as Woosh has said you need a lower wound hub and 201rpm or less is required 48v is better then 36v.